Lock



FIG. 1 is a front perspective view of a lock showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a bottom plan elevation view thereof;

FIG. 5 is a rear view thereof;

FIG. 6 is a right side view thereof; and,

FIG. 7 is a left side view thereof.

The broken lines, which define the bounds of the claimed design, form no part thereof. 

I claim the ornamental design for a lock, as shown and described. 